varying float vSize;
uniform vec3 uColor;

void main() {
    float distanceToCenter = distance(gl_PointCoord, vec2(0.5, 0.5));
    float strength = 1.0 - (distanceToCenter * 2.0);

    if(vSize <= 0.0) {
        gl_FragColor = vec4(1, 0, 0, 0);
    } else {
        gl_FragColor = vec4(uColor, strength);
    }
}